Tracing mantle components and the effect of subduction processes beneath the northern Antarctic Peninsula
Abstract:
Understanding subduction processes is critical in assessing the long-term evolution of the upper mantle and continental crust. We present new geochemical data on glassy submarine lavas from the Bransfield Strait, the Phoenix and West Scotia ridges, and previously unpublished data of marine sediments from atop the Phoenix Plate. We combined new and published geochemical data from across the northern sector of the Antarctic Peninsula to unravel both large-scale mantle composition and flow across the region. The geochemistry of Phoenix and West Scotia Ridge basalts supports the hypothesis that both ridges are underlain by Pacific MORB mantle, brought into the region through the eastward expansion of the Scotia Plate. Our modeling suggests the presence of a more depleted Phoenix MORB mantle beneath the South Shetland Islands modified by the addition ofโ3 % subduction component with a fluid/sediment ratio ranging from 0.18 to 4. The increase in fluid/sediment ratios in the South Shetland Island lavas corresponds to a spatiotemporal progression of volcanism from the southwest (40โ140 Ma) to the northeast (30โ60 Ma). Finally, we have identified a set of lavas with unique trace element and isotope compositions typical of alkaline volcanism found across other parts of the Antarctic Peninsula. Surprisingly, we find occurrences of these lavas on both sides of the South Shetland Trench, suggesting the presence of a distinct enriched source in the upper mantle throughout the region.
How to cite this dataset:
Anderson, D. W., Saal, A. E., Lee, J. I., Mallick, S., Riley, T. R., Keller, R. A., Haase, K. M., 2023. Tracing mantle components and the effect of subduction processes beneath the northern Antarctic Peninsula, Version 1.0. Interdisciplinary Earth Data Alliance (IEDA).
https://doi.org/10.26022/IEDA/112920. Accessed 2024-05-02.
DOI Creation Date:
2023-08-29
Related
Publication(s):
Anderson, D. W., Saal, A. E., Lee, J. I., Mallick, S., Riley, T. R., Keller, R. A., & Haase, K. M. (2023). Tracing mantle components and the effect of subduction processes beneath the northern Antarctic Peninsula. Geochimica et Cosmochimica Acta, 343, 234โ249.
License:
Creative Commons Attribution-ShareAlike 4.0 International [CC-BY-SA-4.0]
Funding source(s):
National Science Foundation:
1643494Keyword(s):
Coverage Scope: Regional (Continents, Oceans)
Geographic Location: Bransfield Strait, Antarctic Peninsula, Phoenix Ridge, Aluk Ridge, West Scotia Ridge, Scotia Sea, Drake Passage, South Shetland Islands
User Contributed Keyword(s):
Bransfield Strait, Phoenix Ridge, subduction, back-arc, arc, geochemistry, basalt, mid-ocean ridge, mantle melting, slab window, mantle dynamics
Data Available On:
2023-08-30